Patent GB-916476-A (GB)
Title: Pattern printer
IPC: B41F15/08
Filed: 1960-07-25
Abstract: 916,476. Stencilling-apparatus; inking-apparatus. TRIGGS, W. W. (ACF Industries Inc.). July 25, 1960, No. 25774/60. Class 100 (2). An apparatus for spray-printing patterns on ceramic wafers comprises a supporting frame, a rotating wheel for receiving and moving wafers in the path of a projected spray, said wheel comprising a medial disc having wafer-receiving notches uniformly formed in its peripheral edge and lateral inner and outer plates of laminated form at each side of the medial disc, said lateral plates projecting beyond the peripheral edge of said medial disc and having stencil-receiving openings about their marginal edge portions opposite the notches in the medial disc, said openings being of smaller diameter in the inner plates to provide outer marginal portions, and stencils of disc form for association with said openings, said stencils including marginal flanges for abutting association with the marginal portions defining the openings in the inner plates. Ceramic wafers E, Fig. 7, are fed down a shoot F, Figs. 1 and 7, into pockets 31, 32 in a continuously rotating wheel A. The wheel A comprises a medial disc 30, Fig. 19, with the pockets equally spaced along its periphery, and two lateral plates 35, 36, each formed of two laminations. The plates 35, 36 are provided with apertures for the reception of stencils 74, Fig. 16, the apertures in the inner laminations being somewhat smaller to form shoulders. The stencils 74 have bevelled faces 73 and flanges 76, and are secured in position by snap-rings 77, being aligned by means of notches 74a engaging pins 74b. Each wafer E between two stencils is passed between two spray guns B, Fig. 1, and C on the opposite side (not shown), to be printed on both sides with the stencil designs. The spray gun C is passed slightly earlier and staggered stationary cams on either side of the wheel act in turn on spring arms 81, pins 79 on the ends of which pass through holes 78 in one stencil and hold the wafer against the opposite stencil. The wafers are allowed to drop under the control of a stop 47 engaging the lowest wafer, and a rubber pad engaging the next lowest, the stop and pad being controlled by a solenoid. The wafers are heated while in the stack, and photo-cell units 310, 291 control the solenoid so that the number of wafers is not reduced too much for the heater to operate, or increased beyond a convenient number. After printing, the wafers fall out between the plates 35, 36 into a container 143. The wheel is then submerged in washing liquid in a container 148, the liquid being supersonically vibrated. Spray nozzles are also used. The wheel then passes between heads 153 (not shown), 152, Fig. 7, in communication with a blower 157, which also blows heated air through a thin vertical opening between converging walls 161 on to the edge of the wheel. Dust and particles are removed by means of a suction head 165, having an adjustable hood 166 having recesses 167 to encompass the outer casings of the spray devices, and communicating with a chamber 169 provided with spaced inclined filter plates. The various components of the machine are actuated by an electrical control system, Fig. 22 (not shown). In another form, Fig. 24, the wheel comprises a medial disc 201 having ceramic wafer pockets, and stencil plates 204, 205 of greater diameter and having pattern openings 206, 208, 211. The wafers are positively seated in the pockets by a spray nozzle 218. Vapours are confined by a hood 220. For drying the wafers, hot air passes through a baffled housing to a spray head 233. The wafers are ejected by a nozzle 240 through a guide 238 into a hopper, remaining wafers falling into a lower pan. The various components are actuated by an electrical control system, Fig. 29 (not shown). This form is particularly used to deposit conductive patterns which constitute the plates of a dielectric capacitor.